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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* Copyright (C) 2019, Raspberry Pi Ltd
*
* cam_helper.h - helper class providing camera information
*/
#pragma once
#include <memory>
#include <string>
#include <libcamera/base/span.h>
#include <libcamera/base/utils.h>
#include "camera_mode.h"
#include "controller/controller.h"
#include "controller/metadata.h"
#include "md_parser.h"
#include "libcamera/internal/v4l2_videodevice.h"
namespace RPiController {
/*
* The CamHelper class provides a number of facilities that anyone trying
* to drive a camera will need to know, but which are not provided by the
* standard driver framework. Specifically, it provides:
*
* A "CameraMode" structure to describe extra information about the chosen
* mode of the driver. For example, how it is cropped from the full sensor
* area, how it is scaled, whether pixels are averaged compared to the full
* resolution.
*
* The ability to convert between number of lines of exposure and actual
* exposure time, and to convert between the sensor's gain codes and actual
* gains.
*
* A function to return the number of frames of delay between updating exposure,
* analogue gain and vblanking, and for the changes to take effect. For many
* sensors these take the values 2, 1 and 2 respectively, but sensors that are
* different will need to over-ride the default function provided.
*
* A function to query if the sensor outputs embedded data that can be parsed.
*
* A function to return the sensitivity of a given camera mode.
*
* A parser to parse the embedded data buffers provided by some sensors (for
* example, the imx219 does; the ov5647 doesn't). This allows us to know for
* sure the exposure and gain of the frame we're looking at. CamHelper
* provides functions for converting analogue gains to and from the sensor's
* native gain codes.
*
* Finally, a set of functions that determine how to handle the vagaries of
* different camera modules on start-up or when switching modes. Some
* modules may produce one or more frames that are not yet correctly exposed,
* or where the metadata may be suspect. We have the following functions:
* HideFramesStartup(): Tell the pipeline handler not to return this many
* frames at start-up. This can also be used to hide initial frames
* while the AGC and other algorithms are sorting themselves out.
* HideFramesModeSwitch(): Tell the pipeline handler not to return this
* many frames after a mode switch (other than start-up). Some sensors
* may produce innvalid frames after a mode switch; others may not.
* MistrustFramesStartup(): At start-up a sensor may return frames for
* which we should not run any control algorithms (for example, metadata
* may be invalid).
* MistrustFramesModeSwitch(): The number of frames, after a mode switch
* (other than start-up), for which control algorithms should not run
* (for example, metadata may be unreliable).
*/
class CamHelper
{
public:
static CamHelper *create(std::string const &camName);
CamHelper(std::unique_ptr<MdParser> parser, unsigned int frameIntegrationDiff);
virtual ~CamHelper();
void setCameraMode(const CameraMode &mode);
virtual void prepare(libcamera::Span<const uint8_t> buffer,
Metadata &metadata);
virtual void process(StatisticsPtr &stats, Metadata &metadata);
virtual uint32_t exposureLines(const libcamera::utils::Duration exposure,
const libcamera::utils::Duration lineLength) const;
virtual libcamera::utils::Duration exposure(uint32_t exposureLines,
const libcamera::utils::Duration lineLength) const;
virtual uint32_t getVBlanking(libcamera::utils::Duration &exposure,
libcamera::utils::Duration minFrameDuration,
libcamera::utils::Duration maxFrameDuration) const;
virtual uint32_t gainCode(double gain) const = 0;
virtual double gain(uint32_t gainCode) const = 0;
virtual void getDelays(int &exposureDelay, int &gainDelay,
int &vblankDelay) const;
virtual bool sensorEmbeddedDataPresent() const;
virtual double getModeSensitivity(const CameraMode &mode) const;
virtual unsigned int hideFramesStartup() const;
virtual unsigned int hideFramesModeSwitch() const;
virtual unsigned int mistrustFramesStartup() const;
virtual unsigned int mistrustFramesModeSwitch() const;
protected:
void parseEmbeddedData(libcamera::Span<const uint8_t> buffer,
Metadata &metadata);
virtual void populateMetadata(const MdParser::RegisterMap ®isters,
Metadata &metadata) const;
std::unique_ptr<MdParser> parser_;
CameraMode mode_;
private:
/*
* Smallest difference between the frame length and integration time,
* in units of lines.
*/
unsigned int frameIntegrationDiff_;
};
/*
* This is for registering camera helpers with the system, so that the
* CamHelper::Create function picks them up automatically.
*/
typedef CamHelper *(*CamHelperCreateFunc)();
struct RegisterCamHelper
{
RegisterCamHelper(char const *camName,
CamHelperCreateFunc createFunc);
};
} /* namespace RPi */
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